The Science of Napping: Fixing Afternoon Slump with R90

It's 2 PM. Your eyelids are heavy, and your brain feels like fog. You decide to take a nap. You wake up feeling worse—headache, groggy, and disoriented.

This is the classic "nap hangover."

Why Does Napping Make You Tired?

It happens because you interrupted a sleep cycle. Once you sleep past 30 minutes, your body enters Deep Sleep. Being forced awake from this stage (by an alarm or noise) causes severe Sleep Inertia. Your brain struggles to switch from deep rest to alertness.

Scientific Napping with R90

According to the R90 method, there are only two efficient ways to take a Controlled Recovery Period (CRP):

1. The "Nano Nap" (< 30 mins)

Duration: 15-20 minutes. Why: You wake up before hitting deep sleep. This clears some adenosine (sleep pressure) and reboots your energy without the grogginess. Tip: Drink a coffee right before napping. Caffeine takes ~20 mins to kick in, waking you up naturally. This is called a "Coffee Nap."

2. The Full Cycle (90 mins)

Duration: 90 minutes. Why: You complete a full cycle (Light-Deep-REM-Light) and wake up naturally during light sleep. When: Use this if you are severely sleep-deprived or on weekends.

Avoid the "Forbidden Zone"

Try to nap between 1 PM and 3 PM. Napping too late (e.g., 5 PM) steals your "sleep pressure," making it hard to fall asleep at night and disrupting your main R90 schedule.

Use the R90 Sleep App to log your naps. It counts them towards your weekly sleep score, reducing anxiety about missed sleep.